To provide means for suppressing both generation of an excess material caused by T.[O] outside an allowable range only known after cutting a cast metal at present and a yield loss caused by a destination change.

A continuous casting method of molten steel is provided in which the T.[O] in the molten steel is analyzed after finishing secondary refining of the molten steel and a continuous casting condition of the molten steel is changed in accordance with the analysis value. In the method, the T.[O] analysis value in the molten steel is known during continuous casting of the molten steel and before cutting the cast metal of the molten steel, and the cast metal is cut in accordance with the known T.[O] analysis value so as to be adapted to the order acceptance content, or the T.[O] analysis value in the molten steel is known before starting injection of the molten steel into a tundish of a continuous casting machine, and a Ca addition quantity to the molten steel is adjusted in accordance with the known T.[O] analysis value so as to be adapted to the order acceptance content.